AG Kommunikationstheorie

Thema:

Implementation and Performance Analysis of Cyclostationary Signature Detection for OFDM-based Cognitive Radio Applications (Diplomvortrag)

Abstract:

Cognitive radio (CR) is the novel approach enabling flexible, efficient and reliable spectrum sharing between primary (PU) and secondary users (SU) by adapting radio operation characteristics to dynamically changing environments. By observing the spectrum of interest CR is able to detect (sense) the unused spectrum and determine transmission characteristics (power, bandwidth, symbol rate) of secondary users. An efficient method for sensing the presence of PU in low SNR regions is cyclostationary feature detection. By embedding a cyclostationary signature in transmitted signal, appropriate detectors can differentiate the PU signal energy from the local noise energy by exploiting certain periodicity exhibited by higher order statistics of a particular modulated signal. Furthermore, Orthogonal Frequency Division Multiplexing (OFDM) is shown to be a potential transmission technology for CR systems due to its flexibility in allocating resources among SU. The frequency characteristics of OFDM additionally allows for easy insertion of cyclostationary signatures over subcarriers. The goal of this thesis is an effective implementation of cyclostationary signatures within the existing GNU Radio-based OFDM testbed developed at TI chair. Furthermore, the performance evaluation of implemented cognitive OFDM-transciever should give insight into deployment issues typical for real communication systems.

The talk will be concluded with the award winning demonstration presented at The Sixth ACM International Workshop on Wireless Network Testbeds, Experimental evaluation and Characterization (WiNTECH 2011).



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